Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: tools lib traceevent: Report better error message on bad function args | Date | Tue, 19 Nov 2013 11:23:56 +0900 |
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Hi Steven,
On Mon, 18 Nov 2013 19:11:31 -0500, Steven Rostedt wrote: > When Jiri Olsa was writing a function callback for > scsi_trace_parse_cdb(), he thought that the traceevent library had a > bug in it because he was getting this error: > > Error: expected ')' but read ',' > Error: expected ')' but read ',' > Error: expected ')' but read ',' > Error: expected ')' but read ',' > > But in truth, he didn't have the write number of arguments for the > function callback, and the error was the library detecting the > discrepancy. A better error message would have prevented the confusion: > > Error: function 'scsi_trace_parse_cdb()' only expects 2 arguments but event scsi_dispatch_cmd_timeout has more > Error: function 'scsi_trace_parse_cdb()' only expects 2 arguments but event scsi_dispatch_cmd_start has more > Error: function 'scsi_trace_parse_cdb()' only expects 2 arguments but event scsi_dispatch_cmd_error has more > Error: function 'scsi_trace_parse_cdb()' only expects 2 arguments but event scsi_dispatch_cmd_done has more > > Or > > Error: function 'scsi_trace_parse_cdb()' expects 4 arguments but event scsi_dispatch_cmd_timeout only uses 3 > Error: function 'scsi_trace_parse_cdb()' expects 4 arguments but event scsi_dispatch_cmd_start only uses 3 > Error: function 'scsi_trace_parse_cdb()' expects 4 arguments but event scsi_dispatch_cmd_error only uses 3 > Error: function 'scsi_trace_parse_cdb()' expects 4 arguments but event scsi_dispatch_cmd_done only uses 3 > > Signed-off-by: Steven Rostedt <rostedt@goodmis.org> > > diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c > index 0362d57..f7aab3d 100644 > --- a/tools/lib/traceevent/event-parse.c > +++ b/tools/lib/traceevent/event-parse.c > @@ -2691,7 +2691,6 @@ process_func_handler(struct event_format *event, struct pevent_function_handler > struct print_arg *farg; > enum event_type type; > char *token; > - const char *test; > int i; > > arg->type = PRINT_FUNC; > @@ -2708,15 +2707,19 @@ process_func_handler(struct event_format *event, struct pevent_function_handler > } > > type = process_arg(event, farg, &token); > - if (i < (func->nr_args - 1)) > - test = ","; > - else > - test = ")"; > - > - if (test_type_token(type, token, EVENT_DELIM, test)) { > - free_arg(farg); > - free_token(token); > - return EVENT_ERROR; > + if (i < (func->nr_args - 1)) { > + if (type != EVENT_DELIM || strcmp(token, ",") != 0) { > + warning("Error: function '%s()' expects %d arguments but event %s only uses %d", > + func->name, func->nr_args, > + event->name, i + 1); > + return EVENT_ERROR; > + } > + } else { > + if (type != EVENT_DELIM || strcmp(token, ")") != 0) { > + warning("Error: function '%s()' only expects %d arguments but event %s has more", > + func->name, func->nr_args, event->name); > + return EVENT_ERROR;
It seems that you missed to free farg and token in error paths.
Thanks, Namhyung
> + } > } > > *next_arg = farg;
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